* { margin: 0; padding: 0; }
html , body { width:100%; height:100%; }
canvas { display: block; }

.container {
  position: relative;
}

.overlay {
  border: 1px solid #fff;
  color: #fff;
  left: 4px;
  padding: 4px;
  position: absolute;
  top: 4px;
}
